用显示器测量办公亮度环境下的人眼对比度敏感视觉特性

对比度敏感是描述人眼视觉系统空间特性的主要指标之一,对比度敏感函数是反映不同条件下的对比度敏感与空间频率之间的关系。人眼对比度敏感数据的测量受到环境亮度较大的影响,为了研究常用办公环境条件下的人眼对比度敏感情况,对6位青年在环境亮度分别为153,312,470 cd/m2和暗室条件下,在距离为2米处观测11种空间频率的矩形光栅进行测量,光栅用显示器进行显示,其平均亮度分别为60和90 cd/m2。实验结果表明,对于相同频率的光栅,人眼对比度敏感程度随着环境亮度的增加而减小,而且人眼在暗室环境下比在办公环境条件下对亮度光栅更敏感;但是在观测平均亮度为60cd/m2的光栅时,人眼特殊地对在环境亮度为312 cd/m2的条件下更敏感。

Measurement Contrast Sensitivity of Human Vision System under Different Office Ambience Luminance Condition on the CRT Display

The contrast sensitivity function(CSF) is one of important and special spatial characteristics of human vision system,which is to reflect the relation between the contrast sensitivity under different viewing condition and spatial frequency.Ambient luminance had much influence on the contrast sensitivity in the measurements.In order to investigate how the luminance of office lighting surround to a visual target affected the measurement of contrast sensitivity to rectangular gratings,six healthy young were examined under the ambient luminance of 153,312,470 cd/m 2 and the dark room condition.Measurements were carried out on a CRT monitor for 11 spatial frequencies at a viewing distance of 2m.Tested grating patterns were with two kinds of average luminance of 60 and 90 cd/m 2.Measurements results show that contrast sensitivity is reduced with ambient luminance increasing,and all contrast sensitivity under the lighting viewing condition was much smaller than one under the dark room viewing condition for the same frequency,but distinguishingly,observers are the most sensitive to gratings under the surround with the luminance of 312 cd/m 2 when viewing the gratings with average luminance of 60 cd/m 2.